We start by working out which era of hardware is actually on the door, not just what the opener badge says. On houses built around 1975, we often find a rail sized for a lighter, older door that's since been swapped for a heavier insulated panel - the opener strains, the gears wear early, and the fix isn't a new logic board, it's a rail and drive matched to the door's actual weight.
Once we know what we're dealing with, the repair itself is usually straightforward: a new drive gear, a replacement circuit board, a properly tensioned belt or chain, or a full head-unit swap if the motor's cooked. We test travel limits, force settings, and safety reversal on every job, not just the part we came to fix, because a door that's been retrofitted piecemeal over 40-plus years rarely has just one thing wrong with it.